Physics: Recent submissions

  • New Li+-ion conductors, Li4 ? 2xTi1 ?xSxO4, based on the Li4TiO4 structure 
    Dissanayake, M.A.K.L.; Sumathipala, H.H.; West, A.R. (Journal of Materials Chemistry, 1994)
    In the system Li4TiO4?Li2SO4, a wide range of solid solutions, Li4 ? 2xSxTi1 ?xO4(0 < x < 0.2) with Li4TiO4 structure is formed. The ionic conductivity increases with x and exhibits a maximum (bulk) value of 8.30 ? 10?6 S ...
  • Novel LISICON mixed conductors, Li4 ? 2xCoxGeO4 
    Sumathipala, H.H.; Dissanayake, M.A.K.L.; West, A.R. (Solid State Ionics, 1996)
    A novel LISICON type ? solid solution range has been found in the system Li4 ? 2xCoxGeO4 for 0.15 ? x ? 0.8. The highest net conductivity, 8.4 ? 10?6Scm?1, was observed for x = 0.25 at 27 �C rising to 3.35 ? 10?3Scm?1 at ...
  • New solid electrolytes and mixed conductors: Li3 + xCr1 ? xMxO4: M = Ge, Ti 
    Dissanayake, M.A.K.L.; Gunawardane, R.P.; Sumathipala, H.H.; West, A.R. (Solid State Ionics, 1995)
    New Li+ ion conducting solid solutions with ?-LISICON type structure have been found in the system Li3 + xCr1 ? xGexO4 for 0.35 < x < 0.92. Conductivity increases with x; at x = 0.90, ? (bulk) ? 1.4 ? 10?5 S cm?1 at 27 �C ...
  • Dual-composite polymer electrolytes with enhanced transport properties 
    Panero S; Scrosati B; Sumathipala H H (Journal of Power Sources, 2007)
    New types of composite, solvent-free lithium ion conducting polymer electrolytes have been prepared by dispersing two complementary additives to a PEO?LiX (LiX = LiCF3SO3) matrix. The additives have been chosen in such a ...
  • Trapping of an electron in coupled quantum dots in graphene 
    Hewageegana, P.; Apalkov, V. (Physical Review B, 2009)
    Due to Klein?s tunneling the electronic states of a quantum dot in graphene have finite widths and an electron in quantum dot has a finite trapping time. This property introduces a special type of interdot coupling in a ...
  • Li-LiFePO4 rechargeable polymer battery using dual composite polymer electrolytes 
    Sumathipala, H.H.; Hassoun, J.; Panero, S.; Scrosati, B. (Journal of Applied Electrochemistry, 2008)
    A composite polymer electrolyte, formed by dispersing into a poly(ethylene oxide)-lithium salt matrix two additives, i.e. calyx(6)pyrrole, (CP) acting as an anion trapper and superacid zirconia, S-ZrO2 acting as a conductivity ...
  • Theoretical study of terahertz quantum well photodetectors: Effect of metallic diffraction coating 
    Hewageegana, P.; Apalkov, V. (Infrared Physics & Technology, 2008)
    The possibility of enhancement of sensitivity of quantum well photodetectors by adding metallic diffraction coating on top of the dielectric layer of photodetectors is studied. With the grating the spatial distribution of ...
  • Enhanced mid-infrared transmission through a metallic diffraction grating 
    Hewageegana, P.; Apalkov, V. (Journal of Physics: Condensed Matter, 2008)
    We study theoretically an enhancement of the intensity of mid-infrared light transmitted through a metallic diffraction grating. We show that for s-polarized light the enhancement of the transmitted light is much stronger ...
  • Second harmonic generation in disordered media: Random resonators 
    Hewageegana, P.; Apalkov, V. (Physical Review B, 2008)
    We theoretically study the effect of random resonators on the conversion efficiency of fundamental mode propagating through disordered nonlinear dielectric film. Only resonators with double-resonant properties, i.e., which ...
  • Electron localization in graphene quantum dots 
    Hewageegana, P.; Apalkov, V. (Physical Review B, 2008)
    We study theoretically a localized state of an electron in a graphene quantum dot with a sharp boundary. Due to Klein?s tunneling, the ?relativistic? electron in graphene cannot be localized by any confinement potential. ...
  • Plasmonic enhancing nanoantennas for photodetection 
    Hewageegana, P.; Stockman, M.I. (Infrared Physics & Technology, 2007)
    This paper discusses the use of plasmonic nanostructured systems as nanoantennas for photodetection. Even though semiconductors and their heterostructures have many useful properties and widely used in photodetection, their ...
  • Quantum dot photodetectors with metallic diffraction grating: Surface plasmons and strong absorption enhancement 
    Hewageegana, P.; Apalkov, V. (Physica E: Low-dimensional Systems and Nanostructures, 2008)
    We report our theoretical study of the effect of metallic diffraction grating on the sensitivity of quantum dot photodetectors in terahertz frequency. We have found that the effect of diffraction grating is much stronger ...
  • Absolute phase effect in ultrafast optical responses of metal nanostructures 
    Stockman, M.I.; Hewageegana, P. (APPLIED PHYSICS A: MATERIALS SCIENCE & PROCESSING, 2007)
    We predict that nonlinear ultrafast electron photoemission by strong optical fields and, potentially, other nonlinear optical responses of metal nanostructures significantly depend on the absolute (carrier?envelope) phase ...
  • Nanolocalized Nonlinear Electron Photoemission under Coherent Control 
    Stockman, M.I.; Hewageegana, P. (Nano Letters, 2005)
    We theoretically show that two-photon coherent control yields electron photoemission from metal nanostructures that is localized in nanosize hot spots whose positions are controllable on a nanometer scale, in agreement ...
  • Vismitha Nano Thakshanaya (??????? ???? ???????) 
    Hewageegana, P. (2012)
  • Graphene Quantum Dots 
    Hewageegana, P.; Apalkov, V. (2010)
  • Multilevel nanoimprint lithography 
    Alkaisi, M.M.; Jayatissa, N.W.K.; Konijn, M. (Current Applied Physics, 2004)
    Multilevel and three-dimensional (3D) patterning eliminates more complicated steps in the fabrication processes of micro and nanoscale structures. Multiple lithography processes with inter-level alignment or single lithography ...
  • Energy use in controlled temperature marine aquaculture 
    Jayatissa, N.W.K.; Davis, C.; Carrington, G.; Chen, G. (International Journal of Energy Research, 2002)
    Temperature control offers benefits in land-based marine aquaculture: stock growth rates may be enhanced by heating in winter; mortality rates in summer may be reduced by cooling. However, if the plant is not well designed, ...
  • Electronic states and local structures of Cu ions in electrodeposited thin films of Cu and Cu2O from X-ray absorption spectra 
    Wijesundera, R.P.; Hidaka, M.; Siripala, W.; Choi Sun-Hee; Sung, N.E.; Kim, M.G.; Lee, J.M. (Physica Status Solidi b (basic solid sates physics), 2006)
    X-ray absorption spectra near Cu K edges have been obtained for Cu and Cu2O thin films potentiostatically electrodeposited in an acetate bath. The electronic states of Cu ions and the local structures around these ions are ...
  • Electrodeposition of p-type, n-type and p-n Homojunction Cuprous Oxide Thin Films 
    Jayathileke, K.M.D.C.; Siripala, W.; Jayanetti, J.K.D.S. (Sri Lankan Journal of Physics, 2008)
    Potentiostatic electrodeposition of cuprous oxide (Cu2O) thin films in aqueous acetate baths was investigated to study the conduction type, n-type or p-type, and the p-n homojunction formation of the films, using photocurrent ...

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